Reaction products of 3-hexenedinitrile and certain aldehydes



Ito the carbon atoms through a double bond, a metbylidyn =CH--,

Patented Feb. 22,1949.

UNITED STATES "PATENT orrica auction 1 ram:

rnonuo'rs or 3-mean onnram amanmrzs Wilmington, no, as-

Carl M. Lourh er r; slgnor to ELduPontdeNemoura a Company,

wilmlngtomllela aeorporation olllelaware No Drawing. Application June 16, 1948, Serialido. 33,442

This invention relates to a new class of organic compounds. having nitrlle groups. More particularly, it relates to substituted 3- hexenedinitriles.

u. s. Patent 2,342,101 discloses and claims as s new product beta-dihydromucononitrlle.

provide new substituted S-hexenedlnitriles. A'

still further object is to provide a method substituting the 1,4-dicyanobutenes which leaves the nitrile groups unaflected and does not remove the double bond. Other objects will appear hereinafter.

These objects are accomplished by providing a new class of chemical compounds, the monomeric condensation products of one mole of a lA-dicyanobutene with two moles of an aldehyde having a double bond conjugated with the carbonyl group. The process of preparing these new compounds comprises reacting, in the presence 01' an alkali metal alkoxlde catalyst. an aldehyde having a double bond conjugated with the carbonyl group with a 1,4-dicyanobutene, i. e., 1,4-dicyano- 2-butene or 1,4-dicyano-l-butene. products are 3-hexenedinitrile's having attached in the 2- and 5-positions group whose remaining valence is attached. to a substltuent having a carbon-to-carbon double bond conjugated with that'oi the methylidyne group. These compounds have the formula Nc-c-cn=cn-c-cN (m-n Oil-R wherein R is the non-0x0 portion of an aldehyde thisinventionito provides- 'hexenedinitriles and the 2,5-di-arallrylidene-2- hexenedinitriles where in each of these classes of compounds there is a methylidyne group attached through a double bond to the carbon atoms in the 2- and 5-positions and also a carbonto-carbon double bond conjugated with that of the methylidyne group.

-1,4-dicyaiio-2-butene may be prepared by the 'Either of the 1,4-dicyanobutenes (hexenedinitriles) may be used as the starting material,

or their mixtures in any proportions. In either case the same. condensation product results.

method of U. S. Patent 2,342,101, or by the improved methods described in applications Ser.

No. 768,283; 768,703 or 768,705. 1,4-dicyano-1- butene is conveniently prepared by isomerization of 1,4-dicyano-2- butene, which may be done, ace

A further object of this invention is to cording to application Ser. No. 756,097, filed by G. F. Hager on June 20, .1947. now PatentNo.

2,451,386 patented October 12, 1948, by malntain- I ing 1,4-dicyano-2-butene at elevated temperatures, e. g., between 60 and 150 C., in the presence of a hydrogenating' metal such as copper or cobalt, until thelA-dicyano-bbutene has formed in substantial amounts. The product is obtained little as 0.02 atom of alkali metal per mole of 40 These new having a carbon-to-carbon double bond coniu gated with the carbonyl group. Thusincluded within this invention are the 2,5-di-allrylidenc-8- as a mixture of the cis and trans isomers, which can' be separated by fractional distillation, al-

though separation is unnecessary ior the purpose of this invention.

The reaction is preferablycarried out by dissolving the 1,4 -dlcyanobutene and the aldehyde to be reacted with it in a suitable alcohol such as methanol, ethanol, isopropyl alcohol. butyl alcohol, etc., and adding to the solution a catalytic amount of an alkali metal alkoxide; e. g., lithium, sodium or potassium alkoxide, which need not necessarily be an alkoxide of the same alcohol used as solvent. There may be used as dicyanobutene, or as much as 0.5 atom or more. The dicyanobutene and the aldehyde are preferably used in at least equivalent proportions, that is, two moles of aldehyde per mole of dicyanobutene. It is oitendesirable to use an excess of the aldehyde, e. g., up to 100% molar excess, to

repress as much as possible the competing reaction whereby the alcohol adds to the double bond.

oi the dicyanobutene.

The reaction is in general exothermic and it is therefore preferably carried out at low to moderate termperatures, e. g., between -10 and 0., although with the less reactive aldehydes it may be desirable to heat the reaction mixture up to C. or higher. The reaction product is in general a crystalline solid which separates from the solution and can be isolated by filtraferred to, which leads to formation of betaalkoxyadiponitriles. there may be formed a cer tain amountoi resinous by-products, so that the yields of the desired substituted 3-hexenedinitrile may vary rather'widely, depending on the reactivity of the aldehyde.

The invention is illustrated in greater detail in f s t t d the following. examples. in which parts are by weight.

- Example I A solution of 63 parts of benzaldehyde and 21.4 parts of 1,4-dicyano-2-butene in 200 parts of absolute ethanol was treated with a solution of 2.8 parts of metallic sodium in 68 parts oi absolute ethanol. added gradually so that the heat eilect due to addition ofa portion of the catalyst --was dissipated before anotherportion was added.

After all the sodium ethoxide solution had been added, the solution was stirred at room temperature for several hours and allowed to stand for 16 hours. Filtering the solution gave 25.3 parts of 2.5-dibenzylidene-3-hexenedinitrile, a bright yellow crystalline solid melting at 246-248 C.

Anal.-Ca lcd. for CzuHuNa: o, 35.1; n, 4.97; n.

9.9; molecular wt'., 282. Found: 5.04; N. 9.65; molecular wt.. 281.

When this experiment. was repeated under similar conditions, but using trans-1,4-dicyanol-butene instead of 1,4-dicyano-2-butene. the

same reaction product was obtained, as identified by melting point and mixed melting point.

/ Erami le II a solution oi-74.4 parts or p-tolualdehyde and 21.4 parts of 1.4-dicyano-2-butene in 200 parts sulfobenzylidene -3-hexenedinitrile. Recrystallized from water the bright yellow monohydrate. which did not melt at 315, wasobtained.

AnaL-Calcd. for cionnosmsmoimoz c. 47.5;

5 n, 2.3; N. 5.5. Found: 1.47.7; 11.3.15; 11.5.45.

. Example V A solution of 22.6 parts of meta-nitrobenzaldehyde and 5.3 parts of 1.4-dicyano-2-butene in 50 parts of a sodium ethoxide solution. After standing for 7 days at room temperature there was obtained by filtration 16.3 parts of 2,5-di-mnitrobenzylidene-3-hexene'dinitrile.

- Example V! a solution r 22.4 parts of p-dimethylaminobenzaldehyde and 5.3 parts of 1.4-dicyano-2- butene in 50 parts of absolute ethanol was treated with 17 parts of 10% sodium ethoxide solution and the reaction mixture was allowed to' stand for 48 hours at room temperature. There was obtained 6.3 parts of 2,5-di-p-dimethylaminobenzylldene-3-hexenedinitrile. a bright red solid which after recrystallization from xylene melted tem-310' c.

Anon-coma. for cumin; 0. 73.3; n. 5.5; N.

15.2. Found: 0. 77.9; 11.5mm. 15.11.

80 Example VII To a solution of 115.2 parts of furfuraldehyde and 42.8 parts of 1.4-dlcyano-2-butene inv 400 parts of absolute ethanol was added dropwise a solution of 2.3 parts of metallic sodium in 68 parts of ethanol, discontinuing the addition at intervals to permit the heat eifect'to subside. The reaction mixture was then allowed to stand for 16 hours'at room temperature and filtered.

of absolute ethanol was treated gradually with a do There was obtained 512 pm of solution of 1 part of metallic sodium in'20 parts of absolute ethanol, interrupting the addition as needed to permit the considerable heatv of reaction to dissipate. The reaction mixture was then Found: C, 03.47; H, 4.03.

stirred for 2 hours and allowed to stand for 16 hours.- Filtration gave 20.2 parts of 2,5-di-pmethylbenzylidene-3-hexenedinitrile, a bright yellow crystalline solid which, after recrystallization from mlene. melted at 265-268? 0..

Anal-Calm. for cnmsm 0.35.13; .530; N,

9.03. Found: 6.84.61: 11.5.73; 11.9.1.

Example III A solution of 20.4 parts of anisaldehyde and 5.3 parts of 1,4-dicyano-2-butene in parts of absolute ethanol was treated with 17 parts of a 10% sodium ethoxide solution. After standing for 24 hours at room temperature. the reaction product was filtered off. It consisted of 7.21 parts of 2.5- di o methoxybenzylidene 3 hexenedinitrile.

station from xylene. melted at 248-251 C.

AnaL-Calcd. for CzaHuOzNz: 'c. 77.5; 11, 5.24;

17, 8.09. Found: c. 75.93; H, 524; n. 3.12.

Example IV 80 This was a. yellow solid which. after recrystalliidene-3-hexenedinitrile, 'an orange-redsolid which. after recrystallization from xylene, melted at 225-227 C.

Ami-coma. for C18H1002N22 c, 7323; n. 3.32.

Example VIII 50 absolute ethanol was treated with a solution of 1 part of metallic sodium in 30 parts of ethanol. When the heat eflect had subsided. which re- .quired about '2 hours. the reaction mixture was filtered. There was obtained 27 parts of 2,5-dicrotonylidene-3-hexenedinitrile. which after two recrystallizations from absolute alcohol melted at 154-155 C.

AiulL-Calcd. for GuHrsNa: N, 13.35. Found: N.

solution or 1 part ofmetallic sodium in 30 parts I] of absolute ethanol, discontinuing the addition at intervals to permit the heat effect to subside. After the reaction mixture had been allowed to stand for 16 hours at room temperature. it was filtered. giving 29 parts of 2,5-di-clnnamylidene- 3-hexenedinitrile. After recrystallization from xylene this material melted at 245-248 C.

diml -coma. forCuHraNa: c. 35.3; H, 5.45; s,

8.88. Found: C. 85.66; H. 5.59; lfl. 8.18.

There m y be used in the process oi this invention any-aldehyde having a cai'bon to carbon double bond conjugated with the carbonyl group,

such as aromatic. aliphatic, .cycloaliphatic or heterocyclic aldehydes, including, in addition to those used in the examples, acrolein, citral, alphaand beta-methylcrotonaldehyde, l-cyclohexenyi aldehyde, piperonal, naphthaldehyde, anthraldehyde, alpha-pyrrolaldehyde, alpha-'thiophenaldehyde and the like. Thus, the compounds of this invention include in addition to those shown in the example, 3-hexenedinitriies having in'the, 2- and 5-positions groups such as acrylidene, citryiidene, alpha methylcrotonylidene, betamethylcrotonylidene. 'l-cyclohexenyli'dene, piperonylidene, naphthylidene, anthrylidene. alphapyrrylidene, alpha-thienylidene and the like. The

aldehydes suitable for this invention mayfbear various substltuents such as thealkoxy, aryloxy,'

sulto, halo, nitro, amino, dialkylamino, hydroiry,

- thio, carboxy, carbalkoxy etc., groups, including groups which under certain conditions'react with the dicyanobutenes, since the reaction 01 the aidehyde groups is rapid and leads to substantial colored." They contain 'tem otgconjugated double bonds, and they are a new chromophoric wetherefore useful asdyelstufls per se, for example,

as dispersion colors tor-cellulose acetate.

As many 'appar tly widely diilerent embodiments'ot this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention isnot limited to the specific embodiments thereof except as de lined in the appended claims.

Iclaimr g I .1. A 3-hexenedin'itrile having a methylidyne group attachedthrough adouble bond to the carbon atom in the 2'-position and another methylidyne group attached through a double bond. to the carbon atom in'the S-position. the remaining valence of eachof jsaidimethylidyne groups-bein amounts of compounds of the type described even J when competing reactive groups are present. Thus, the only important portion of the molecule from the standpoint of this reaction isthe aldehyde group conjugated with an ethylenic double bond. The preferred materials, because of their greater ease of formation and of separation from the reaction mixture, are the 3-hexenedinitriles having in the 2- and 5-positions, substituents or from 3 to 18 carbon atoms, and preferably alkylidene or aralkylidene substituents.

The products of this invention are useful as intermediates in the synthesis 0i! many chemicals through the reactions or the nitrile groups and of? attached to sepiiatecarbon atoms which have a -carbon-to-carbon .double bond conjugated with that of the-methylidyne group.

2. A 2,5-di-aralkylidene-2-hexenedinitrilehaving a-carbon to-carbon double bond conjugated with that of the methylidyne group.

3. 2,5-di-benzylidene-3 hexenedinitriie.

4. A 2,5-dialkylidene-3-hexenedinitrile having a carbon to-carbon double bond conjugated with that'ot the methylidyne group.-

5. 2,5-di-furiurylidene-3-hexenedinitrile.

6. The-method which comprises reacting in the presence or an alkali metal alkoxide catalyst a 1,4-dicyanobutene with an aldehyde having a double bond conjugated with the carbonyl group.

7.- The method as set iorth in claim 6 inwhlch the aldehyde is an aromatic aldehyde having a the unsaturated linkages. For example, they may be hydrogenated partly or completely,thus lead-' ing to saturated nitriles'or to saturated or unsaturated diamines; or they may be hydrolyzed to diamides or dicarboxylic acids- The products thus obtained are in turn useful as polyamide intermediates, plasticizer intermediates, dyestui'! intermediates, etc. As has already been noted. the products of this invention, in particular those having aralkylidene substituents. are highly cyanobutene withbenzaldehyde.

10. The, method which comprises reacting in I the presence oi an alkali metal alkoxide catalyst a.1,4-dicyanobutene with furiuraldehyde.

' CARL Li. LANGKAMMERER.

No references cited.

Certificate of Correction Patent'No; 2,4 2,407. Y I February 22, 1949.

CARL M. LANGKAMMERER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 21, claim 2, for 2,5-di-aralky1idene-2-hexenedinitrile" read' I 2,5-di-amllcylidene-S-hexenedinitrile and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case 1n the Patent Oflice,

Signed and sealed this 26th day of July, A. D. 1949.

THOMAS F. MURPHY, v Assistant Uommiasioneroflatenta. 

